Turn webspeech on/off when tab goes fore/background

content/common/speech_recognition_messages.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Multiply-included message file, hence no include guard.
 
 #include <string>
 
 #include "content/public/common/speech_recognition_error.h"
 #include "content/public/common/speech_recognition_grammar.h"
@@ skipping 52 matching lines @@
   // Whether the user requested interim results or not.
   IPC_STRUCT_MEMBER(bool, interim_results)
 IPC_STRUCT_END()
 
 
 // Requests the speech recognition service to start speech recognition.
 IPC_MESSAGE_CONTROL1(SpeechRecognitionHostMsg_StartRequest,
                      SpeechRecognitionHostMsg_StartRequest_Params)
 
 // Requests the speech recognition service to abort speech recognition on
-// behalf of the given |render_view_id|. If speech recognition is not happening
-// or is happening on behalf of some other render view, this call does nothing.
+// behalf of the given |render_view_id| and |request_id|. If there are no
+// sessions associated with the |request_id| in the render view, this call
+// does nothing.
 IPC_MESSAGE_CONTROL2(SpeechRecognitionHostMsg_AbortRequest,
                      int /* render_view_id */,
                      int /* request_id */)
 
+// Requests the speech recognition service to abort all speech recognitions on
+// behalf of the given |render_view_id|. If speech recognition is not happening
+// or is happening on behalf of some other render view, this call does nothing.
+IPC_MESSAGE_CONTROL1(SpeechRecognitionHostMsg_AbortAllRequests,
+                     int /* render_view_id */)
+
 // Requests the speech recognition service to stop audio capture on behalf of
 // the given |render_view_id|. Any audio recorded so far will be fed to the
 // speech recognizer. If speech recognition is not happening nor or is
 // happening on behalf of some other render view, this call does nothing.
 IPC_MESSAGE_CONTROL2(SpeechRecognitionHostMsg_StopCaptureRequest,
                      int /* render_view_id */,
                      int /* request_id */)
 
 // Browser -> Renderer messages.
 
@@ skipping 11 matching lines @@
 
 IPC_MESSAGE_ROUTED1(SpeechRecognitionMsg_AudioStarted, int /* request_id */)
 
 IPC_MESSAGE_ROUTED1(SpeechRecognitionMsg_SoundStarted, int /* request_id */)
 
 IPC_MESSAGE_ROUTED1(SpeechRecognitionMsg_SoundEnded, int /* request_id */)
 
 IPC_MESSAGE_ROUTED1(SpeechRecognitionMsg_AudioEnded, int /* request_id */)
 
 IPC_MESSAGE_ROUTED1(SpeechRecognitionMsg_Ended, int /* request_id */)